单晶碳和锗薄膜热导率的分子动力学模拟

Molecular dynamic simulation thermal conductivity of single/crystal carbon and germanium thin films

采用非平衡分子动力学（NEMD）方法分别模拟碳和锗纳米薄膜的法向热导率.模拟结果表明：厚度为2～5nm的碳晶体薄膜在温度为300～500K的法向热导率显著小于对应的大体积晶体的实验值,并随薄膜厚度的增加而增加,法向热导率与薄膜厚度呈近似线性关系；厚度为2.8175～11.27nm的单晶锗纳米薄膜在温度为300～500K时的法向热导也存在明显的尺寸效应,薄膜的热导率与其厚度呈近似线性关系,并且随着薄膜厚度的增加而增加.

NEMD calculations are employed for the thermal conductivity of single crystal carbon and germanium films in normal direction. The results of calculations demonstrate that, at the temperature ranging from 300 to 500 K, the thermal conductivity in normal direction of the crystal carbon films with the thickness of about 2～5 nm is remarkably lower than the corresponding experimental data of the bulk, and rises with the increase of the film thickness in a approximate linear trend; as for the germanium film with the thickness of about 2.8175～11.27 nm, in the temperature range of 300～500 K, the size effect on the thermal conductivity remains notable and the thermal conductivity also rises with the increase of the film thickness in a approximate linear trend; the thermal conductivity of the crystal carbon and germanium films decreases with the increase of the temperature.